Well one can conceive, physically at least, the OTL KMT achieving a "victory" by exhausting the Japanese to the point where they simply give up and withdraw back into Northeast China. That's pretty much the upper-limit of what they could manage, but at least it's something that isn't ASB...
That doesn't seem at all unreasonable... probably the most likely outcome if Japan had managed to avoid expanding their enemies. They were pretty much limited to what they could reach logistically and had reached those limits with the final Ichi Go offensive being about as good as it was likely to ever get.
Although that is still very tough on the Chinese